Orsino, who is in love with Olivia, tries to beguile the time with music while his latest advocate, Valentine, tries to persuade Olivia to requite Orsino’s love. Alas, the distraction the music affords Orsino is temporary, and worse Valentine arrives to report the following: Olivia will sequester herself for seven years while mourning for her recently deceased brother. Which is to say, no, Olivia shall not requite Orsino’s love. Dismayed, Orsino seeks solace in a bower of flowers.
Chance has brought Viola, who has lost Sebastian (her brother) out at sea, to the coast of an unfamiliar land. When told by the Captain of the ship that they are on the coast of Illyria, Viola mentions her childhood memory of the Duke of Illyria, of the then Duke’s bachelor status. The Captain tells Viola that on account of a rich countess who has thwarted the Duke’s overtures of love, that the Duke remains a bachelor to this day. The news prompts Viola to take a course of action that would place her in the service of the Duke. She would like to offer the Duke what solace she can. To pull this off, she would need to disguise herself as a eunuch. She entreats the Captain for his help and he obliges.
On behalf of Olivia, Maria rebukes Sir Toby Belch for staying out too late, for excessive drinking, and for keeping company with profligates the likes of Sir Andrew Aguecheek. Sir Toby is defiant, however, dismissing Olivia’s objections as hackneyed and standing up for his friend with praises that Maria is only too glad to debunk and does debunk. Nonetheless, Sir Toby, determined to reverse the pervading gloom and sorrow that Olivia has cast on the house, persuades Sir Andrew to extend his sojourn, arguing that as Olivia will on no account requite the Duke‘s overtures of love that his--Sir Andrew‘s--prospects of wooing her is not a lost cause. Thus persuaded, Sir Andrew humors Sir Toby who has grand plans for them both, plans involving dancing and festivities galore.
Though only three days have passed since beginning her term of service, Viola, who is now Cesario, is so highly regarded by Orsino that she/he is commissioned to plead Olivia on the Duke’s behalf. Cesario doubts that he’ll make any difference, but Orisno, citing Cesario’s feminine voice and appeal, insists that he will. Cesario consents to do Duke’s bidding despite harboring an inner conflict: Cesario, a.k.a. Viola, is in love with the Duke.
Though rebuked by Maria for an impropriety, Feste, taking full advantage of his fool’s license, remains as irreverent as ever. The irreverence is unabated vis-à-vis Olivia and Malvolio. When asked to comment upon Feste’s irreverence, Malvolio’s words are so mean-spirited that Olivia accuses Malvolio--her steward--of putting himself on a pedestal and of lacking perspective. Anon, Olivia is informed that her uncle is at the gates attending to a messenger who wishes to speak with her. Lest her uncle cause mischief (as he is wont to do), Olivia sends Malvolio to attend to the messenger, reminding him that if the messenger is from the Duke with a message pertaining to the Duke’s love for Olivia, then Malvolio is to turn the messenger away, justifying the denial with a made-up excuse or another. Presently, Olivia confronts her uncle whose drunkenness is cause for concern. Her concern is such that she has Feste attend on him. Anon, Malvolio returns to report his failure to carry out Olivia’s commission, attributing his failure to the messenger’s youth and cheeky boldness. Malvolio is asked to describe this messenger. He is neither man or boy, Malvolio says, and he speaks with a sharp tongue. Intrigued (as the Duke's messengers were typically grave, elderly men), Olivia decides to give this new, young messenger her time of day. Having covered her face with a veil and attended by Maria, Olivia goes out to meet him.
As reported, Cesario, the Duke’s new messenger, is young, feminine, persistent and saucy. He dedicates Olivia with a tribute that is so blatantly flattering that Olivia understands it to mean that Cesario finds Olivia haughty and arrogant. How dare she reject the Duke of Illyria’s overtures of love as if they were trifling trinkets! As a measure of concession, Olivia removes her veil to reveal her face. Cesario continues to flatter Olivia, in effect rebuking Olivia for being too proud. Regardless, Olivia remains firm in her resolve to reject the Duke’s overtures. If anything, Olivia is impressed with the young messenger. She is so impressed with Cesario that after Cesario’s departure she has Malvolio deliver Cesario a ring under a false pretext.